Most brokerages have gradually begun letting investors purchase fractional shares of virtually any stock they support. However, a few still don't, making a $20 weekly contribution to a retirement account seem quite underwhelming when looking at the many stocks trading above $100 or even $1,000.

But fear not -- today we will look at three multibillion-dollar enterprises whose stock prices trade below this $20 threshold in SoFi Technologies (SOFI -1.79%)Coupang (CPNG 2.60%), and Nu Holdings (NU 1.88%).

With each young growth stock either recently becoming profitable or poised to report positive net income by generally accepted accounting principles (GAAP) in 2023, investors would be wise to hold these stellar stocks forever.

1. SoFi Technologies

Through three distinct yet interwoven business segments -- lending, technology platform, and financial services -- SoFi Technologies is quietly building a digital-era financial powerhouse.

After receiving a bank charter designation early in 2022, SoFi launched full speed into developing its youngest business line, financial services. Now offering checking, savings, investment, and credit card accounts, the company's nascent banking services unit reported 60% year-over-year growth in the number of financial products used in the fourth quarter of 2022. 

While the fledgling segment only accounts for 14% of SoFi's total revenue (and is still unprofitable) it plays a crucial role in the company's ambitions for GAAP profitability in 2023. Here's how.

Officially becoming a bank in February 2022, SoFi has accelerated growth in its total deposits from $1 billion to $7.3 billion in less than a year. With 88% of this growth from members making direct deposits into checking and savings accounts, the banking unit has armed SoFi with precious low-cost funding for its core lending unit.

Regarding the importance of this $7.3 billion, CFO Chris LaPointe clarified that the cost of these deposits is about 190 basis points cheaper than other funding methods for its loans. LaPointe would further explain that this lower-cost funding would save SoFi about $125 million annually -- which is about 8% of the company's sales from 2022. 

Riding this favorable tailwind, management expects to become GAAP profitable by the fourth quarter of 2023. Guiding for a minimum of 25% sales growth in 2023, SoFi's continued expansion and reasonable price-to-sales ratio under 4 makes it a tremendous buy-and-hold-forever investment with profitability seemingly en route

2. Coupang

Recording a GAAP net income margin of 2% and a free cash flow (FCF) margin of 9% in its most recent quarter, South Korean e-commerce juggernaut Coupang continued to show the benefits of its streamlining efficiencies. While Coupang only saw a 1% increase in active customers in the fourth quarter of 2022 compared to the same period a year earlier, its Wow memberships (think Amazon Prime) grew by 20% to 11 million members.

Priced at about $50 a year, Wow members receive free shipping and returns, same-day grocery delivery, exclusive discounts, and access to Coupang Play, the company's streaming video service. These members are crucial to Coupang's success, as they not only contribute directly to free cash flow and net income with their subscription fees, but also spend multiples more than their non-member peers.

Best yet, the company's oldest customer cohorts from 2018 and 2019 continue shopping more and more, increasing their spending by 4.7 and 3.6 times, respectively, compared to their first-year purchase totals. Even more encouraging, each new cohort has spent more in their first year than the previous year's group did.

Recording 21% sales growth (minus foreign exchange impacts) in Q4 2022, Coupang's ongoing developments in fintech, streaming, logistics, and advertising create precious growth optionality for the long haul. Trading at just 1.3 times sales, Coupang could be a top-tier lifelong holding if it can maintain this newfound free cash flow generation going forward 

3. Nu Holdings

Helmed by CEO and founder David Vélez, Brazilian-based (and Warren Buffett-backed) Nubank is a rising star in the banking industry -- but has yet to gain traction on the public markets.

Previously in charge of investments in Latin America at Sequoia Capital, Vélez founded Nubank in 2013 because he was disappointed by the antiquity and unfairness of the banking system in Brazil. One decade later, Nubank is a $23 billion fintech that just grew its revenue by 112% (minus foreign exchange impacts) year over year in its most recent quarter.

Now 75 million customers strong, the young bank already counts 44% of the adult population in Brazil as customers. Of these customers, 58% say Nubank is their primary banking account.

While most young companies' growing sales by over 100% tend to be unprofitable, Nubank recorded $8 million in net income in Q3 and another $50 million in Q4 after removing a one-time, non-cash item. Better yet, despite this incredible growth, the company's percentage of non-performing loans after 90 days continues to be well below market averages.

Last but not least, Nubank's coverage ratio, compared to its non-performing loans, is above 200%, leaving the company conservatively positioned to face any struggles from its credit card or personal loan underwriting. 

The cherry on top of it all?

Nubank is just beginning its expansion plans into Mexico and Colombia, where it only has 3% and 2% of the adult population as customers. While it will be crucially important to watch the company's loan performance very closely each quarter, the appealing risk-reward ratio on Nubank's stock makes it a perfect pick to add $20 to and hold forever.